在 android 中面临图像上传和检索到数据存储的困难？

Question

我已经搜索了一些答案，但可能是我的错，找不到我想要的answer.Now低于我正在尝试的答案：
I am trying to upload an image like of a status or a post or any profile pic.Profile pic will be small and status or any post image will be big。现在我想做什么：

1. 我正在将图像转换为字符串文本并将其上传到数据存储，它的限制是 1Mbyte.So 我想在上传图像时检查它是否超过限制。

2. 我想检查图像是否为 png format.If 它不是然后不会 upload.Show Toast.Can 我在那里转换图像？ :(

3. 如果用户正在上传假设 700kbyte 的图片，但个人资料图片很小，即 100kbyte 就足够用于个人资料图片，那么我可以将图片压缩到我定义的大小，然后将其上传到 datastore.It 可能会保持 700kbyte如果是状态图。

我正在将图像转换为字符串并将其上传到数据存储区，然后在我的应用程序中显示它时再次转换回图像。My code:

public static String imageToStringConverter(Bitmap image){
    ByteArrayOutputStream stream = new ByteArrayOutputStream();
    image.compress(Bitmap.CompressFormat.PNG, 100, stream);
    byte[] byteArray = stream.toByteArray();
    String imageToString = Base64.encodeToString(byteArray, Base64.NO_WRAP);

    return imageToString;
}

public static Bitmap stringToimageConverter(String imageString){
    byte[] stringTobyte = Base64.decode(imageString, Base64.NO_WRAP);
    Bitmap bmp = BitmapFactory.decodeByteArray(stringTobyte, 0, stringTobyte.length);
    return bmp;
}

现在我面临的问题 :

1。当我上传正在拍摄的图片时 time.So 我应该在将图片转换为我想要的大小后在上传时使用 asynctask 吗？？

2。当我第一次进入我的应用程序时，我显示了个人资料图片，即如果我登录我的帐户，它将从 datastore.But 获取个人资料图片，这需要很多时间而且我的登录似乎很长。

Answer 1

我已经通过缩小图像解决了我的问题。这是我的代码：

public void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
        super.onActivityResult(requestCode, resultCode, imageReturnedIntent);

        switch (requestCode) {

            case SELECT_PHOTO:
                Uri imageUri;
                try {
                     imageUri = imageReturnedIntent.getData();
                }catch(Exception e){
                    Toast.makeText(getActivity(),"Image Not Found",Toast.LENGTH_SHORT).show();
                    return;
                }
                //final InputStream imageStream = getActivity().getContentResolver().openInputStream(imageUri);
                //final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);
                ShrinkBitmapConverter sh = new ShrinkBitmapConverter(getActivity());
                Bitmap selectedImage = null;
                try {
                    selectedImage = sh.shrinkBitmap(imageUri,450,350);
                } catch (Exception e) {
                    Toast.makeText(getActivity(),"Image Not Found",Toast.LENGTH_SHORT).show();
                }
                statusImage = ImageConverter.imageToStringConverter(selectedImage);
                if(statusImage.length()>512000){
                    Toast.makeText(getActivity(),"Image is too big",Toast.LENGTH_LONG).show();
                }else {
                    postImage.setImageBitmap(selectedImage);
                }
        }
    }

ImageConverter.java:

public class ImageConverter {

    public static String imageToStringConverter(Bitmap image){
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        image.compress(Bitmap.CompressFormat.PNG, 100, stream);
        byte[] byteArray = stream.toByteArray();
        String imageToString = Base64.encodeToString(byteArray, Base64.NO_WRAP);
        return imageToString;
    }

    public static Bitmap stringToimageConverter(String imageString){
        byte[] stringTobyte = Base64.decode(imageString, Base64.NO_WRAP);
        Bitmap bmp = BitmapFactory.decodeByteArray(stringTobyte, 0, stringTobyte.length);
        return bmp;
    }

}

ShrinkBitmapConverter.java:

public class ShrinkBitmapConverter {
    Context context;
    public ShrinkBitmapConverter(Context c){
        context=c;
    }

    public Bitmap shrinkBitmap(Uri uri,int width,int height) throws FileNotFoundException {

        BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
        bmpFactoryOptions.inJustDecodeBounds = true;

        Bitmap bitmap = null;;
        try {
            bitmap = BitmapFactory.decodeStream(context.getContentResolver().openInputStream(uri),null,bmpFactoryOptions);

            int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);
            int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);

            if (heightRatio > 1 || widthRatio > 1)
            {
                if (heightRatio > widthRatio)
                {
                    bmpFactoryOptions.inSampleSize = heightRatio;
                } else {
                    bmpFactoryOptions.inSampleSize = widthRatio;
                }
            }

            bmpFactoryOptions.inJustDecodeBounds = false;
            bitmap = BitmapFactory.decodeStream(context.getContentResolver().openInputStream(uri),null,bmpFactoryOptions);

        } catch (Exception e) {

            Toast.makeText(context,"Image Not Found",Toast.LENGTH_SHORT).show();
        }

        return bitmap;
    }
}

在 android 中面临图像上传和检索到数据存储的困难？

Facing Image Uploading and retrieving difficulties to Datastore in android?

android

image

google-app-engine

image-uploading

image-conversion